Arrays constructed with a known element count (literals, slices, map/filter results) reserved at least four slots, so a one-element literal took a 48-byte block for 9 bytes of content. Construction now allocates exactly the requested slots, and any dense capacity is rounded up to fill its small-object allocator block (1 slot -> 16 B, 2-3 -> 32 B). Appends below four slots grow straight to four and double from there as before. The first storage of an array is a plain allocation with its states cleared, without the realloc, state move and sparse absorption of later growth. New capacity still starts as holes.
Malte Ubl
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